These were taken over the last year or so of Mek, the Malayan Tiger mother at the San Diego Zoo, and her two sons, Christopher and Conner. I can't tell for sure in some of them, but it's generally Christopher who stays closest to his mother - and who generally elicits the strongest reaction at times. She's not yawning in this first shot. He was about 3 1/2 months old when this was taken.
About 2 seconds after I shot this next one, she bit him on the back of the neck and chased him off. You can see more of this particular interaction in the sequence of shots in this post.
Even though the cubs are a lot bigger now, I think they know that their mother is still in charge. Or, if they act like they've forgotten that, she is quick to remind them.
So, Happy Mother's Day to Mek, and all other mothers out there.